First, there are plans for hotels 5, 6, and 7 right now. Hotel 5 will have approximately 1,000 rooms and convention space. Hotel 6 will only be built if Universal decides not to build 400 additional rooms planned for Cabana Bay resort, and would be 400 rooms itself. Hotel 7 seems to be only 400 rooms as well, but I have to read that section again before confirming that.
But with all that, what will the theme of Hotel 5 be? We all know the land is currently sitting there waiting to be built upon, so Universal has to have a theme in mind, right? Well, it seems like they do, and it's one they've already used before. From these plans, it looks as if Hotel 5 and the oft rumored Royal Pacific Resort expansion will be one in the same. The picture below clearly shows the new buildings on the site between RP and Cabana Bay, and is marked "Royal Pacific First Addition" on the plans.
The following picture shows the entrance to the new expansion, which will be off Adventure Way.
The following three pictures include where the pedestrian bridge connecting the new convention space to the existing convetion space at RPR, a mockup of the bridge, and the rerouted Hollywood Way plans. These pictures also give a good diea what the setup of the new addition will be, minus the amenities such as the pool, restaurants, etc.
As always, stay tuned to Parkscope for more updates.
After reading through more of the documents and a post on Orlando United, and seeing hints from a few more knowledgable people across twitter and the forums, I wanted to update the post with some better information. First, while the fifth hotel does seem to be connected to Royal Pacific physically and in theme, there are hints/specualtion from people such as Teebin on Orlando United and Seth Kubersky that it is more of a sister hotel than a straight expansion. The documents back that up as well. This hotel will NOT have Express Pass included according to the documentation, which means it will not be a part of the same hotel. It's also seemingly positioned at a price point between the original hotels and Cabana Bay, according to the documents. Suites are also mentioned, though I don't know if it's an incidental mention or an indication of what the property will include.
The most important part, however, is the transportation section. Looks like this hotel will indeed have water taxi access, as the documents say the following: Theme Park Owner shall be responsible for providing bus or other vehicular transportation services and ferryboat transportation services for transporting the Fifth Hotels and Theme Park guests between the Fifth Hotel and the Theme Park. This leads me to believe the hotel will be the "moderate" choice with a price point between Royal Pacific and Cabana Bay.